Fall Quiz 2

Question 0

What is the difference between a compensatory and non compensatory premature beat?

Answer 0

A compensatory premature beat will have QRS complexes that march out evenly before and after the pause.

Question 1

What is a premature beat?

Answer 1

When an irritable ectopic focus fires prematurely.

Question 2

What is an escape beat?

Answer 2

When the SA node doesn’t fire at its regular interval and an ectopic focus fires.

Question 3

What is a reentry circuit?

Answer 3

A group of cardiac cells that depolarize in a circular pattern that is rapid and repetitive.

Question 4

What is the underlying mechanism of most tachydysrhytmias?

Answer 4

Reentry circuits

Question 5

What are the 2 types of reentry circuits?

Answer 5

Macroentry & Microentry

This refers to the amount of tissue that is affected by the circuit.

Question 6

List the 3 conditions necessary to establish a reentry circuit.

Answer 6

1. Two separate parallel paths of impulse conduction.
2. Slowed conduction or complete unidirectional block in one of the pathways.
3. The right timing of the absolute refractory period.

Question 7

What is Wolf Parkinson White Syndrome? (WPW)

Answer 7

A macroreentry pathway where an accessory pathway provides secondary access to the ventricles.

Question 8

List 6 types of Atrial Rhythms.

Answer 8

W:  Wandering atrial pacemaker (WAP)
E:  Ectopic atrial tachycardia (EAT)
A:  Atrial Fibrillation (AFib)
P:  Premature atrial contraction (PAC)
M:  Multifocal atrial tachycardia (MAT)
A:  Atrial Flutter

Question 9

Explain WAP

Answer 9

• Regular to irregularly irregular
• Wandering Atrial Pacemaker
• Pacemaker shifts between multiple foci (impulse origins)
• must have at least 3 different p-wave morphologies
• normal rate (60-100)
• normal QRS (less than 0.12)

Question 10

Explain MAT rhythm.

Answer 10

• Regular to irregularly irregular
• Multifocal Atrial Tachycardia
• Tachycardic version of WAP
• 3 different pwave morphologies
• Less common than, and easy to confuse with AFib
• look for inverted pwaves to differentiate from AFib

Question 11

Explain PAC rhythm.

Answer 11

• Premature Atrial Contraction
• Results from premature discharge of an ectopic atrial focus.
• characterized by a premature abnormal pwave.
• pwave may be buried in twave.

Question 12

List 3 causes of PAC

Answer 12

Caffeine
Sympathomimetics
Hypoxia

Question 13

What is a nonconducted PAC

Answer 13

It is a premature atrial contraction from an ectopic focus that is not transmitted through the AV node, resulting in a premature pwave with no corresponding QRS.

Question 14

Explain EAT rhythm.

Answer 14

• Ectopic Atrial Tachycardia
• regular rhythm
• results from increased automaticity from an ectopic atrial focus or microreentry circuit.

Question 15

Explain AFib.

Answer 15

• Atrial fibrillation
• caused by many irritable atrial foci firing at once, causing chaos.
• only some impulses are transmitted through the AV node resulting in irregularly irregular rhythm.
• PRI: non-existent
• QRS: <0.12

Question 16

List some etiology of AFib.

Answer 16

• Atrial enlargement
• Age
• Pericarditis
• Coronary artery disease
• MI
• hypertension
• Alcohol abuse

Question 17

List 2 problems associated with chronic AFib.

Answer 17

• Reduced cardiac output

* blood clots formed in the atria can lead to embolism or stroke

Question 18

Explain Atrial Flutter

Answer 18

• rapid discharge of single ectopic focus causing atrial rate of 250-500 (usually 300)
• usually a regular rhythm
• is an example of a macro-reentry circuit
• rare - usually converts on its own.

Question 19

Name the 4 junctional rhythms.

Answer 19

PJC: Premature Junctional Contraction
Junctional rhythm
Accelerated junctional rhythm
Junctional tachycardia

Question 20

Describe what junctional p-waves look like.

Answer 20

No p-wave or inverted p-wave and occasionally retrograde

p-waves.

Question 21

Describe a PJC.

Answer 21

Premature junctional contraction.
Caused by a premature discharge of an ectopic focus in the AV node.
Absent, inverted, or retrograde p-waves.
Usually a regular underlying rhythm.

Question 22

Explain junctional rhythm.

Answer 22

Rhythm that originates in the AV node as the SA node has either slowed or failed.
Rhythm: regular
Rate: 40-60
P-waves: absent, inverted or retrograde
QRS: narrow

Question 23

What is accelerated junctional rhythm?

Answer 23

Same as junctional rhythm with a rate of 60-100

Question 24

What is junctional tachycardia?

Answer 24

Same as junctional rhythm with a rate over 100

Question 25

Describe AVNRT

Answer 25

AV node reentrent tachycardia About 10% of population have 2 pathways through the AV node Sometimes a reentry circuit develops if the conditions are right *regular *very rapid *no discernible p-waves *narrow QRS

Question 26

Describe AVRT.

Answer 26

AV reentrant tachycardia Can occur when an accessory pathway connects the atria and ventricles WPW (wolf Parkinson white) is the most common

Question 27

List the 4 rhythms that are very difficult to tell apart and that (for this class) are referred to as SVT (supraventricular tachycardia)

Answer 27

EAT: ectopic atrial tachycardia Junctional tachycardia AVNRT AVRT

Question 28

What is the general formula for Determining a patients natural maximum heart rate (sinus heart rate)?

Answer 28

220-age. | This formula can help determine between SVT and sinus tach

Question 29

How do you differentiate an inverted junctional p-wave from an inverted atrial p-wave?

Answer 29

PRI less than 0.12 is considered junctional. | PRI longer than 0.12 is considered atrial.

Question 30

By definition, where do all ventricular rhythms originate?

Answer 30

In the ventricles, below the bundle of His

Question 31

Describe ventricular QRS complexes?

Answer 31

They are ALL wide

Question 32

Define and describe a PVC

Answer 32

Premature Ventricular Contraction * results from an ectopic focus in the ventricles * no p-wave * wide QRS, often distorted or bizarrely shaped

Question 33

What is the difference between a unifocal and Multifocal PVC?

Answer 33

Unifocal have the same focus, Multifocal have numerous foci.

Question 34

What is bigeminy? Trigeminy?

Answer 34

Bigeminy: when every other beat is a PVC Trigeminy: when every 3rd beat is a PVC

Question 35

Name 6 etiology of PVC's

Answer 35

``` Sympathomimetics Hypoxia Caffeine Idiopathic Myocardial ischemia Electrolyte imbalance ```

Question 36

What are the characteristics of Ventricular Escape Rhythm?

Answer 36

``` Rhythm: regular Rate: less than 40 P-waves: none PRI: none QRS: wide, sometimes bizarre ```

Question 37

List 3 etiology of ventricular escape rhythm

Answer 37

Damage to higher pacemaker Complete heart block First successful rhythm following defibrillation

Question 38

What is accelerated Ventricular rhythm?

Answer 38

Same as ventricular rhythm with a rate of 40-100

Question 39

Describe ventricular tachycardia

Answer 39

Rhythm: regular or slightly irregular Rate: greater than 100-250

Question 40

List 4 vtach etiology

Answer 40

``` Acute MI Myocardial ischemia Electrolyte imbalances Acid base disturbances **nearly all vtachs occur because of micro reentry circuits due to slow or non-conducting tissue ```

Question 41

What is Torsades de Pointes?

Answer 41

A polymorphic vtach Frequently occurs in the setting of prolonged QT Treated with mag sulfate

Question 42

Why is prolonged QTI problematic?

Answer 42

Because of the excessive relative refractory period.

Question 43

Describe Vfib.

Answer 43

Completely chaotic electrical activity in the ventricles. | Always pulseless.

Question 44

Name 5 etiology of Vfib.

Answer 44

``` MI Hypoxia Electrolyte imbalances Electrical shock Drugs ```

Question 45

Describe asystole.

Answer 45

No electrical activity | Final ECG in all deaths

Question 46

Describe bundle branch blocks.

Answer 46

Must originate supraventrically Wide QRS Can be identified generically in lead II 12-lead needed to differentiate the side of the block

Question 47

What type of pacemaker only fires when the intrinsic ones fail?

Answer 47

A "demand" pacemaker

Question 48

Define the term "ventricular capture"

Answer 48

When a pacemaker spike is followed by a wide QRS

Question 49

Define "intrinsic beat"

Answer 49

A beat from the hearts own rhythm.

Question 50

Define a fusion beat.

Answer 50

A complex formed when a paced beat fires simultaneously with an intrinsic beat.